dht-relay-wss/lib/instrument.js

hyperswarm-dht-relay websocket server with some instrumentation

const metricsPlugin = require('fastify-metrics') // TODO: upgrade to current major
const instrument = require('hyper-instrument')

function setupHealthEndpoint (dhtRelay) {
  dhtRelay.app.get('/health', { logLevel: 'warn' }, function (req, reply) {
    if (dhtRelay.opened !== true) {
      reply.status(503)
      reply.send('Service not yet ready')
    } else if (dhtRelay.closing) {
      reply.status(503)
      reply.send('Service shutting down')
    } else {
      reply.status(200)
      reply.send('Service healthy')
    }
  })
}

function instrumentRelay (dhtRelay, logger, {
  prometheusAlias, prometheusSharedSecret, prometheusScraperPublicKey, prometheusServiceName
}) {
  setupHealthEndpoint(dhtRelay)

  let dhtPromClient = null
  const setupPromRpcClient = prometheusAlias != null
  if (setupPromRpcClient) {
    dhtPromClient = instrument({
      dht: dhtRelay.dht,
      scraperPublicKey: prometheusScraperPublicKey,
      prometheusAlias,
      scraperSecret: prometheusSharedSecret,
      prometheusServiceName
    })

    dhtPromClient.registerLogger(logger)
  }

  dhtRelay.app.register(metricsPlugin, {
    defaultMetrics: { enabled: false }, // We manage these ourselves
    endpoint: '/metrics',
    routeMetrics: {
      routeBlacklist: ['/health', '/metrics']
    }
  })

  return dhtPromClient
}

module.exports = instrumentRelay